Sanding?
Try sanding the affected area. If the wood underneath the mold is soft, then it should probably be replaced. If you have to go that route, while you've got the floor ripped up (in that section) then I'd recommend checking the sub-floor for damage as well.
If the wood underneath the mold is just as hard as the rest of the floor, then it should be ok....at least for another year, anyway. Just re-finish that area (it's not in the middle of the floor, is it?) and deal with it for another year.
You could also possibly just toss a throw-rug over the spot once it's refinished (temporarily)...
-YendorMike
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